This paper reports measurements of both the spectral and specular thermal radiation emission characteristics of very regularly microconfigured grooved surfaces in a silicon substrate at 300 and 400°C. The resulting surfaces were phosphorus-doped, to assure the dominance of the emission from the material near the sample surface. The samples had groove depths H of zero for a reference, to 42 μm, and widths L = 12.6 to 14 μm. The geometry repeat distance was 22 μm, or 455 grooves per cm. The grooves correspond directly in size to the band of principle emission wavelengths λ that arises at these temperature levels. The measurements show strong spectral effects for normal emission, including highly favored frequencies, for H > λ. This suggests a cavity “organ pipe” mode of emission. Similar, though modified, effects were found in directional emission, away from the normal. There also were strong polarization effects, with the cross-groove polarization mode dominant. The spectral and specular measurements are compared with calculations of the classical kind, which tacitly assume that λ < < H = 0(L).
Toward transformable photonics: Reversible deforming soft cavities, controlling their resonance split and directional emission
